[lldb/Plugins] Add memory writing capabilities to Scripted Process

This patch adds memory writing capabilities to the Scripted Process plugin.

This allows to user to get a target address and a memory buffer on the
python scripted process implementation that the user can make processing
on before performing the actual write.

This will also be used to write trap instruction to a real process
memory to set a breakpoint.

Signed-off-by: Med Ismail Bennani <medismail.bennani@gmail.com>

lldb/test/API/functionalities/scripted_process/TestScriptedProcess.py

@@ -150,7 +150,6 @@ class ScriptedProcesTestCase(TestBase):
         self.assertEqual(process_1.GetNumThreads(), 1)
 
         # ... then try reading from target #1 process ...
-        addr = 0x500000000
         message = "Hello, target 1"
         buff = process_1.ReadCStringFromMemory(addr, len(message) + 1, error)
         self.assertSuccess(error)
@@ -158,12 +157,22 @@ class ScriptedProcesTestCase(TestBase):
 
         # ... now, reading again from target #0 process to make sure the call
         # gets dispatched to the right target.
-        addr = 0x500000000
         message = "Hello, target 0"
         buff = process_0.ReadCStringFromMemory(addr, len(message) + 1, error)
         self.assertSuccess(error)
         self.assertEqual(buff, message)
 
+        # Let's write some memory.
+        message = "Hello, world!"
+        bytes_written = process_0.WriteMemoryAsCString(addr, message, error)
+        self.assertSuccess(error)
+        self.assertEqual(bytes_written, len(message) + 1)
+
+        # ... and check if that memory was saved properly.
+        buff = process_0.ReadCStringFromMemory(addr, len(message) + 1, error)
+        self.assertSuccess(error)
+        self.assertEqual(buff, message)
+
         thread = process_0.GetSelectedThread()
         self.assertTrue(thread, "Invalid thread.")
         self.assertEqual(thread.GetThreadID(), 0x19)