[TensorExpr] Cleanup IRPrinter implementation for statements. (#37050)
Summary:
Pull Request resolved: https://github.com/pytorch/pytorch/pull/37050
With this change curly braces are printed as a part of Block rather than
a part of the enclosing statement. It allows us, for instance, to more
easily see nested blocks: now they will be printed each in its own
curly-braced scope.
As a side effect, I had to change how we print loop options. Previously
we did it like this:
```
for (...) { // <loop options>
<loop body (Block)>
}
```
Now, since everything in between { and } is a part of the block, we have
to do it the following way:
```
for (...) /* <loop options> */ {
<loop body (Block)>
}
```
Note the change from '//' to '/* .. */' for the loop option comments.
Test Plan: Imported from OSS
Differential Revision: D21171851
Pulled By: ZolotukhinM
fbshipit-source-id: 39f51a9e15aec03b6527b0634fd4b9e01a912cda
Author
Mikhail Zolotukhin
