LibJS: Allocate 4 KiB for Bytecode::BasicBlock

There's no reason not to, since we're using mmap() for these anyway
and that gives us memory in 4 KiB increments. :^)

Userland/Libraries/LibJS/Bytecode/BasicBlock.cpp

@@ -22,7 +22,7 @@ BasicBlock::BasicBlock(String name)
     // FIXME: This is not the smartest solution ever. Find something cleverer!
     // The main issue we're working around here is that we don't want pointers into the bytecode stream to become invalidated
     // during code generation due to dynamic buffer resizing. Otherwise we could just use a Vector.
-    m_buffer_capacity = 1 * KiB;
+    m_buffer_capacity = 4 * KiB;
     m_buffer = (u8*)mmap(nullptr, m_buffer_capacity, PROT_READ | PROT_WRITE, MAP_ANONYMOUS | MAP_PRIVATE, 0, 0);
     VERIFY(m_buffer != MAP_FAILED);
 }