Feat: add fdiv constant folding support and enhance mapping debug info

[YanzhouTang]

Summary

In this PR, we add constant folding support for fdiv, and enhance some debug info during mapping.

The mapping info after each attempt of II now is organized with table like below (take II = 5 for example):

Tile    | t%5=0                              | t%5=1                              | t%5=2                              | t%5=3                              | t%5=4                              | 
--------+------------------------------------+------------------------------------+------------------------------------+------------------------------------+------------------------------------+
Tile#0   |                                     |                                     | %31 = grant_predicate(%29, %30) (t=7) |                                     |                                     | 
Tile#4   |                                     | %11 = grant_once(%10) (t=6)         |                                     |                                     |                                     | 
Tile#8   | %9 = fdiv(%8) (t=5)                 | %53 = load_indexed(%52) (t=6)       | %3 = grant_once                     |                                     |                                     | 
Tile#9   | %51 = phi(%49, %50) (t=5)           | %136 = add(%135) (t=6)              |                                     |                                     | %25 = grant_predicate(%23, %24)     | 
Tile#10  |                                     | %17 = icmp(%16)                     |                                     |                                     |                                     | 
Tile#11  | %1 = constant                       |                                     | %19 = grant_once(%18)               |                                     |                                     | 
Tile#12  | %5 = fdiv(%4) (t=5)                 | %7 = grant_once(%6) (t=6)           | %55 = sext(%54) (t=7)               | %65 = load_indexed(%64) (t=8)       | %2 = constant                       | 
Tile#13  | %59 = load_indexed(%58) (t=10)      | %13 = fdiv(%12) (t=6)               | %28 = grant_predicate(%26, %27) (t=7) | %63 = load_indexed(%62) (t=8)       |                                     | 
Tile#14  |                                     |                                     | %15 = grant_once(%14) (t=7)         |                                     |                                     | 

Each cell shows the operation and operands and corresponding mapping time so that we can easily check mapping status using modular scheduling.

[tancheng]

Can we also have a test to check the dumpped (beautified) log?

[YanzhouTang]

Can we also have a test to check the dumpped (beautified) log?

Add dump-mapping-table parameter in --map-to-accelerator PASS, if it is true, we'll dump successful mapping status table. An example can be found in test/c2llvm2mlir/simple_loop/test.mlir

Also name the below constants as constexpr