Convert validate.sh to cabal-validate

Closes haskell#10317.

A Haskell script will be easier to maintain and expand than the existing
Bash script.

This also adds a `--pattern PATTERN` option which lets you filter tests
across all test suites.

Makefile

@@ -29,16 +29,16 @@ init: ## Set up git hooks and ignored revisions
 
 .PHONY: style
 style: ## Run the code styler
-	@fourmolu -q -i Cabal Cabal-syntax cabal-install
+	@fourmolu -q -i Cabal Cabal-syntax cabal-install cabal-validate
 
 .PHONY: style-modified
 style-modified: ## Run the code styler on modified files
-	@git ls-files --modified Cabal Cabal-syntax cabal-install \
+	@git ls-files --modified Cabal Cabal-syntax cabal-install cabal-validate \
 		| grep '.hs$$' | xargs -P $(PROCS) -I {} fourmolu -q -i {}
 
 .PHONY: style-commit
 style-commit: ## Run the code styler on the previous commit
-	@git diff --name-only HEAD $(COMMIT) Cabal Cabal-syntax cabal-install \
+	@git diff --name-only HEAD $(COMMIT) Cabal Cabal-syntax cabal-install cabal-validate \
 		| grep '.hs$$' | xargs -P $(PROCS) -I {} fourmolu -q -i {}
 
 # source generation: SPDX

cabal-validate/cabal-validate.cabal

@@ -0,0 +1,37 @@
+cabal-version: 3.0
+name:          cabal-validate
+version:       1.0.0
+copyright:     2024-2024, Cabal Development Team (see AUTHORS file)
+license:       BSD-3-Clause
+author:        Cabal Development Team <cabal-devel@haskell.org>
+synopsis:      An internal tool for building and testing the Cabal package manager
+build-type:    Simple
+
+common warnings
+    ghc-options: -Wall
+
+executable cabal-validate
+    import: warnings
+    default-language: Haskell2010
+    default-extensions:
+        OverloadedStrings
+        , TypeApplications
+    ghc-options: -O -threaded -rtsopts -with-rtsopts=-N
+
+    if impl(ghc <9.6)
+        -- Pattern exhaustiveness checker is not as good, misses a case.
+        ghc-options: -Wno-incomplete-patterns
+
+    main-is: Main.hs
+    hs-source-dirs: main
+
+    build-depends:
+        base >=4 && <5
+        , ansi-terminal >=1 && <2
+        , turtle >=1 && <2
+        , optparse-applicative >=0.18 && <1
+        , containers >=0.6 && <1
+        , directory >=1.0 && <2
+        , text >=2 && <3
+        , terminal-size >=0.3 && <1
+        , time >=1 && <2