[10/15][Clang][RISCV][NFC] Don't need to check for `MaskPolicy` in `isTAPolicy` and `isTUPolicy`

[eopXD]

Summary

Caller of the two utilities is always companied with a predicate to
check for !IsMask, so we don't need to check for the mask policy
here.

This also removes dependency to Policy::PolicyType::Omit, which will
be removed.

This is the 10th 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]

Rebase upon latest main.

[eopXD]

Bump CI.

[kito-cheng]

LGTM

clang/include/clang/Support/RISCVVIntrinsicUtils.h

struct Policy {
   bool isTUMAPolicy() const {
     return TailPolicy == Undisturbed && MaskPolicy == Agnostic;
   }
 
   bool isTUMUPolicy() const {
     return TailPolicy == Undisturbed && MaskPolicy == Undisturbed;
   }
 
-  bool isTAPolicy() const {
-    return TailPolicy == Agnostic && MaskPolicy == Omit;
-  }
+  bool isTAPolicy() const { return TailPolicy == Agnostic; }
 
-  bool isTUPolicy() const {
-    return TailPolicy == Undisturbed && MaskPolicy == Omit;
-  }
+  bool isTUPolicy() const { return TailPolicy == Undisturbed; }
 
   bool isMAPolicy() const { return MaskPolicy == Agnostic; }
 
   bool isMUPolicy() const { return MaskPolicy == Undisturbed; }
 
   bool hasTailPolicy() const { return HasTailPolicy; }
 
   bool hasMaskPolicy() const { return HasMaskPolicy; }