[fir] Update clang-tidy for the Optimizer directory

Update .clang-tidy file with the value used in fir-dev.

This patch is part of the upstreaming effort from fir-dev branch.

Reviewed By: rovka

Differential Revision: https://reviews.llvm.org/D111525

Co-authored-by: Valentin Clement <clementval@gmail.com>

flang/include/flang/Optimizer/.clang-tidy

@@ -1,9 +1,19 @@
 Checks: '-readability-braces-around-statements,readability-identifier-naming,llvm-include-order,clang-diagnostic-*'
 InheritParentConfig: true
 CheckOptions:
+  - key:             readability-identifier-naming.ClassCase
+    value:           CamelCase
+  - key:             readability-identifier-naming.EnumCase
+    value:           CamelCase
+  - key:             readability-identifier-naming.FunctionCase
+    value:           camelBack
   - key:             readability-identifier-naming.MemberCase
     value:           camelBack
   - key:             readability-identifier-naming.ParameterCase
     value:           camelBack
+  - key:             readability-identifier-naming.UnionCase
+    value:           CamelCase
   - key:             readability-identifier-naming.VariableCase
     value:           camelBack
+  - key:             readability-identifier-naming.IgnoreMainLikeFunctions
+    value:           1

flang/lib/Optimizer/.clang-tidy

@@ -1,9 +1,19 @@
 Checks: '-readability-braces-around-statements,readability-identifier-naming,llvm-include-order,clang-diagnostic-*'
 InheritParentConfig: true
 CheckOptions:
+  - key:             readability-identifier-naming.ClassCase
+    value:           CamelCase
+  - key:             readability-identifier-naming.EnumCase
+    value:           CamelCase
+  - key:             readability-identifier-naming.FunctionCase
+    value:           camelBack
   - key:             readability-identifier-naming.MemberCase
     value:           camelBack
   - key:             readability-identifier-naming.ParameterCase
     value:           camelBack
+  - key:             readability-identifier-naming.UnionCase
+    value:           CamelCase
   - key:             readability-identifier-naming.VariableCase
     value:           camelBack
+  - key:             readability-identifier-naming.IgnoreMainLikeFunctions
+    value:           1