[lldb] Convert assertTrue(a == b) to assertEqual(a, b)

Convert `assertTrue(a == b)` to `assertEqual(a, b)` to produce better failure messages.

These were mostly done via regex search & replace, with some manual fixes.

Differential Revision: https://reviews.llvm.org/D95813

lldb/test/API/python_api/process/read-mem-cstring/TestReadMemCString.py

@@ -48,11 +48,11 @@ class TestReadMemCString(TestBase):
         # None object.
         empty_str = process.ReadCStringFromMemory(empty_str_addr, 2048, err)
         self.assertTrue(err.Success())
-        self.assertTrue(empty_str == "")
+        self.assertEqual(empty_str, "")
 
         one_letter_string = process.ReadCStringFromMemory(one_letter_str_addr, 2048, err)
         self.assertTrue(err.Success())
-        self.assertTrue(one_letter_string == "1")
+        self.assertEqual(one_letter_string, "1")
 
         invalid_memory_string = process.ReadCStringFromMemory(invalid_memory_str_addr, 2048, err)
         self.assertTrue(err.Fail())