[2/15][Clang][RISCV][NFC] Rename Policy::IsPolicyNone to IsUnspecifed

[eopXD]

Summary

The original naming is inaccurate. An RVV intrinsic always comes with
a corresponding policy behavior. When the policy is unspecified for an
intrinsic, its policy behavior should be it's default assumption.

This is the 2nd commit of a patch-set that aims to change the default policy
for RVV intrinsics from TAMU to TAMA.

Please refer to the cover letter in the 1st commit (D141573) for an
overview.

[eopXD]

Bump CI

[eopXD]

Bump CI

[eopXD]

Rebase to latest main.

[kito-cheng]

LGTM, this made the code more expressive.

[craig.topper]

clang/include/clang/Support/RISCVVIntrinsicUtils.h

96

Maybe this should default to true, and the constructor that wants false should set it to false? Then you can use = default for the default constructor.

clang/lib/Support/RISCVVIntrinsicUtils.cpp

921

This can be folded into the previous if using &&.

[eopXD]

For the record here, IsUnspecified will be removed in D142016, so the un-addressed comment will be resolved by then.