Remove regex functionality from rbcrun

As a first step to making .rbc files compatible with bazel,
remove regex support since bazel doesn't have it.

Fixes: 227384703
Test: ./out/rbcrun ./build/make/tests/run.rbc
Change-Id: I8b946c20cc42897a47a5516a167732f4e16b6158

tools/rbcrun/testdata/regex.star

@@ -1,13 +0,0 @@
-# Tests rblf_regex
-load("assert.star", "assert")
-
-
-def test():
-    pattern = "^(foo.*bar|abc.*d|1.*)$"
-    for w in ("foobar", "fooxbar", "abcxd", "123"):
-        assert.true(rblf_regex(pattern, w), "%s should match %s" % (w, pattern))
-    for w in ("afoobar", "abcde"):
-        assert.true(not rblf_regex(pattern, w), "%s should not match %s" % (w, pattern))
-
-
-test()